/*
 * Copyright 2009 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.collectplus.express.tools.barcode;

import java.util.Hashtable;

/**
 * <p>
 * Encapsulates functionality and implementation that is common to UPC and EAN families of one-dimensional barcodes.
 * </p>
 * 
 * @author aripollak@gmail.com (Ari Pollak)
 */
public abstract class UPCEANWriter implements Writer {
	/**
	 * Start/end guard pattern.
	 */
	static final int[] START_END_PATTERN = { 1, 1, 1, };

	public BitMatrix encode(String contents, BarcodeFormat format, int width, int height) throws Exception {
		return encode(contents, format, width, height, null);
	}

	public BitMatrix encode(String contents, BarcodeFormat format, int width, int height, Hashtable<String, BarcodeFormat> hints) throws Exception {
		if (contents == null || contents.length() == 0) {
			throw new IllegalArgumentException("Found empty contents");
		}

		if (width < 0 || height < 0) {
			throw new IllegalArgumentException("Requested dimensions are too small: " + width + 'x' + height);
		}

		byte[] code = encode(contents);
		return renderResult(code, width, height);
	}

	/** @return a byte array of horizontal pixels (0 = white, 1 = black) */
	private static BitMatrix renderResult(byte[] code, int width, int height) {
		int inputWidth = code.length;
		// Add quiet zone on both sides
		int fullWidth = inputWidth + (START_END_PATTERN.length << 1);
		int outputWidth = Math.max(width, fullWidth);
		int outputHeight = Math.max(1, height);

		int multiple = outputWidth / fullWidth;
		int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;

		BitMatrix output = new BitMatrix(outputWidth, outputHeight);
		for (int inputX = 0, outputX = leftPadding; inputX < inputWidth; inputX++, outputX += multiple) {
			if (code[inputX] == 1) {
				output.setRegion(outputX, 0, multiple, outputHeight);
			}
		}
		return output;
	}

	/**
	 * Appends the given pattern to the target array starting at pos.
	 * 
	 * @param startColor
	 *            starting color - 0 for white, 1 for black
	 * @return the number of elements added to target.
	 */
	protected static int appendPattern(byte[] target, int pos, int[] pattern, int startColor) {
		if (startColor != 0 && startColor != 1) {
			throw new IllegalArgumentException("startColor must be either 0 or 1, but got: " + startColor);
		}

		byte color = (byte) startColor;
		int numAdded = 0;
		for (int i = 0; i < pattern.length; i++) {
			for (int j = 0; j < pattern[i]; j++) {
				target[pos] = color;
				pos += 1;
				numAdded += 1;
			}
			color ^= 1; // flip color after each segment
		}
		return numAdded;
	}

	/** @return a byte array of horizontal pixels (0 = white, 1 = black) */
	public abstract byte[] encode(String contents);

}
